Medicaments for the treatment of gastrointestinal dysfunction

ABSTRACT

The invention relates to the use of compounds of the general formula (I) ##STR1## wherein R 1  represents a hydrogen atom or a C 1-10  alkyl, C 3-7  cycloalkyl, C 3-7  cycloalkyl-(C 1-4 ) alkyl, C 3-6  alkenyl, C 3-10  alkynyl, phenyl or phenyl-C 1-3  alkyl group; and one of the groups represented by 
     R 2 , R 3  and R 4  is a hydrogen atom or a C 1-6  alkyl, C 3-7  cycloalkyl, C 2-6  alkenyl or phenyl-C 1-3  alkyl group and each of the other two groups, which may be the same or different represents a hydrogen atom or a C 1-6  alkyl group; 
     and physiologically acceptable salts and solvates thereof in combination with ranitidine, for the treatment of gastrointestinal dysfunction including the relief of nausea and vomiting, the promotion of gastric emptying, and the treatment of dyspepsia, reflux oesophagitis, flatulence, peptic ulcer, and gastric stasis.

This application is a Division of application Ser. No. 07/501,974, filedMar. 30, 1990; which is a Continuation of application Ser. No.07/315,314, filed Feb. 24, 1989 (now abandoned); which is a Division ofapplication Ser. No. 07/177,042, filed Apr. 4, 1988 (now U.S. Pat. No.4,929,632); which is a Division of application Ser. No. 06/877,805,filed Jun. 24, 1986 (now U.S. Pat. No. 4,753,789).

This invention relates to a new medical use for a group of heterocycliccompounds and pharmaceutical compositions containing them. In particularit relates to certain tetrahydrocarbazolone derivatives which may beused to promote gastric emptying and as anti-emetic agents.

A particularly important application for anti-emetic agents is in theprevention and treatment of nausea and vomiting associated with cancerchemotherapy. Emesis is a well-known and frequent side-effect of cancerchemotherapeutic agents, such as cisplatin. It causes serious problemsin cancer chemotherapy, and in some patients emesis is so severe thattherapy must be discontinued. Anti-emetic agents are therefore oftenadministered in order to alleviate this side-effect of the cancerchemotherapeutic agent. The anti-emetic agents employed are usuallybenzamide derivatives, such as metoclopramide, which have dopamineantagonist activity.

Metoclopramide is also a gastric motility stimulant, i.e. it promotesgastric emptying. The promotion of gastric emptying is important in thetreatment of gastro-intestinal disorders related to gastric stasis; andin radiological examinations.

In view of their dopamine antagonist activity benzamide derivatives suchas metoclopramide themselves exhibit serious and undesirableside-effects, such as extra-pyramidal effects, i.e. tardive dyskinesia,acute distonia, akathisia and tremor. There is thus a need for a safeand effective anti-emetic agent and gastric motility stimulant.

In our British patent application No. 2153821A and our European patentapplication No. 86300423 we disclose3-imidazolylmethyltetrahydrocarbazolones which may be represented by thegeneral formula (I) ##STR2## wherein R¹ represents a hydrogen atom or aC₁₋₁₀ alkyl, C₃₋₇ cycloalkyl, C₃₋₇ cycloalkyl-(C₁₋₄)alkyl, C₃₋₆ alkenyl,C₃₋₁₀ alkynyl, phenyl or phenyl-C₁₋₃ alkyl group, and one of the groupsrepresented by R², R³ and R⁴ is a hydrogen atom or a C₁₋₆ alkyl, C₃₋₇cycloalkyl, C₂₋₆ alkenyl or phenyl-C₁₋₃ alkyl group and each of theother two groups, which may be the same or different, represents ahydrogen atom or a C₁₋₆ alkyl group;

and physiologically acceptable salts and solvates, e.g. hydrates,thereof.

Suitable physiologically acceptable salts of the carbazolones of generalformula (I) includes acid addition salts formed with organic orinorganic acids for example, hydrochlorides, hydrobromides, sulphates,phosphates, citrates, fumarates and maleates. The solvates may, forexample, be hydrates.

The aforementioned specifications also disclose physiologicallyacceptable equivalents of the compounds of formula (I), i.e.physiologically acceptable compounds which are converted in vivo intothe parent compound of formula (I).

The compounds of formula (I) are described in the aforementionedspecifications as potent and selective antagonists of5-hydroxytryptamine (5-HT) at `neuronal` 5-HT receptors of the typelocated on terminals of primary afferent nerves, and which are alsobelieved to be present in the central nervous system. The compounds aredescribed as being of use in the treatment of a human or animal subjectsuffering from a condition caused by a disturbance of neuronal 5HTfunction, for example in the treatment of a human subject suffering frommigraine pain or a psychotic disorder such as schizophrenia. It is alsostated that the compounds may be useful in the treatment of conditionssuch as anxiety, obesity and mania.

We have now surprisingly found that compounds of formula (I) promotegastric emptying and also that they are anti-emetic.

Accordingly, the invention provides a method of treatment for the reliefof nausea and vomiting, and/or the promotion of gastric emptying e.g.for the relief of gastro-intestinal disorders associated with gastricstasis, which comprises administering to a human or animal subject aneffective amount of a compound of formula (I), or a physiologicallyacceptable salt or solvate thereof.

Tests in animals have shown that compounds of formula (I) enhancegastric emptying. The compounds are therefore of use in the treatmentand/or prevention of conditions which may be relieved by the promotionof gastric emptying e.g. gastric stasis which may occur, for example,post-operatively, and symptoms of gastro-intestinal dysfunction such asoccur with dyspepsia, peptic ulcer, reflux oesophagitis and flatulence.The compounds may also be used to promote gastric emptying in diagnosticradiological procedures, such as radiological examinations.

Tests in animals have also shown that compounds of formula (I) inhibitemesis. The compounds are therefore also of use as anti-emetic agents,i.e. in the prevention and treatment of nausea and vomiting. Thecompounds are especially valuable for the prevention of emesis inducedby cancer chemotherapeutic agents such as cisplatin. Particular mentionmay also be made of the treatment of radiation-induced emesis. Thus, thecompounds of formula (I) may be used in the prevention of emesis inducedby radiation therapy, e.g. irradiation of the thorax or abdomen, such asin the treatment of cancer; or in the treatment of radiation sickness.

The compounds of formula (I) do not possess dopamine antagonist activityand thus will not produce the undesirable side effects found with knownanti-emetic agents such as metoclopramide.

It will be appreciated that the compounds of formula (I) may be usedprophylactically and references in this specification to treatmentinclude prophylactic treatment as well as the alleviation of acutesymptoms.

A preferred class of compounds for use according to the invention isthat represented by the formula (Ia): ##STR3## (wherein R¹.sbsp.arepresents a hydrogen atom or a methyl, ethyl, propyl, prop-2-yl,prop-2-enyl or cyclopentyl group; R³.sbsp.a represents a hydrogen atom;and either R².sbsp.a represents a methyl, ethyl, propyl or prop-2-ylgroup and R⁴.sbsp.a represents a hydrogen atom or R².sbsp.a represents ahydrogen atom and R⁴.sbsp.a represents a methyl or ethyl group) andphysiologically acceptable salts and solvates (e.g. hydrates) thereof.

Preferred compounds for use according to the present invention are:

1,2,3,9-tetrahydro-3-[(2-methyl-1H-imidazol-1-yl)methyl]-9-(prop-2-enyl)-4H-carbazol-4-one;

9-cyclopentyl-1,2,3,9-tetrahydro-3-[(2-methyl-1H-imidazol-1-yl)-methyl]-4H-carbazol-4-one;and

1,2,3,9-tetrahydro-3-[(2-methyl-1H-imidazol-1-yl)methyl]-9-(prop-2-yl)-4H-carbazol-4-oneand their physiologically acceptable salts and solvates.

A particularly preferred compound is1,2,3,9-tetrahydro-9-methyl-3-[(2-methyl-1H-imidazol-1-yl)methyl]-4H-carbazol-4-one,and the physiologically acceptable salts and solvates (e.g. hydrates)thereof. A preferred form of this compound is the hydrochloridedihydrate.

The compounds of formula (Ia) are well absorbed from thegastro-intestinal tract. They do not prolong sleeping time in thepentobarbitone anaesthetised mouse indicating that there is noundesirable interaction with drug metabolising enzymes. Indeed theyexhibit no effects on normal behaviour, are non-toxic and exhibit noundesirable effects in mice at doses up to 1 mg/kg intravenously.

Accordingly, the invention also provides a pharmaceutical compositionwhich comprises at least one compound selected from3-imidazolylmethyltetrahydrocarbazolone derivatives of the generalformula (I), their physiologically acceptable salts and solvates, e.g.hydrates, for use in human or veterinary medicine, for the relief ofnausea and vomiting and/or the promotion of gastric emptying e.g. forthe relief of gastro-intestinal disorders associated with gastricstasis.

In a yet further aspect, the invention provides the use of a compound offormula (I) or a physiologically acceptable salt or solvate thereof, forthe manufacture of a medicament for the relief of nausea and vomiting,and/or the promotion of gastric emptying e.g. for the relief ofgastro-intestinal disorders associated with gastric stasis.

Pharmaceutical compositions for use in accordance with the presentinvention may be formulated in conventional manner using one or morephysiologically acceptable carriers or excipients.

Thus the compounds of formula (I) and their physiologically acceptablesalts and solvates may be formulated for oral, buccal, parenteral orrectal administration or in a form suitable for administration byinhalation or insufflation (either through the mouth or the nose).

For oral administration, the pharmaceutical compositions may take theform of, for example, tablets or capsules prepared by conventional meanswith pharmaceutically acceptable excipients such as binding agents (e.g.pregelatinised maize starch, polyvinylpyrrolidone or hydroxypropylmethylcellulose); fillers (e.g. lactose, microcrystalline cellulose orcalcium hydrogen phosphate); lubricants (e.g. magnesium stearate, talcor silica); disintegrants (e.g. potato starch or sodium starchglycollate); or wetting agents (e.g. sodium lauryl sulphate). Thetablets may be coated by methods well known in the art. Liquidpreparations for oral administration may take the form of, for example,solutions, syrups or suspensions, or they may be presented as a dryproduct for constitution with water or other suitable vehicle beforeuse. Such liquid preparations may be prepared by conventional means withpharmaceutically acceptable additives such as suspending agents (e.g.sorbitol syrup, cellulose derivatives or hydrogenated edible fats);emulsifying agents (e.g. lecithin or acacia); non-aqueous vehicles (e.g.almond oil, oily esters, ethyl alcohol or fractionated vegetable oils);and preservatives (e.g. methyl or propyl-p-hydroxybenzoates or sorbicacid). The preparations may also contain buffer salts, flavouring,colouring and sweetening agents as appropriate.

Preparations for oral administration may be suitably formulated to givecontrolled release of the active compound.

For buccal administration the compositions may take the form of tabletsor lozenges formulated in conventional manner.

The compounds of formula (I) may be formulated for parenteraladministration by injection e.g. by bolus injection or continuousinfusion. Formulations for injection may be presented in unit dosageform e.g. in ampoules or in multi-dose containers, with an addedpreservative. The compositions may take such forms as suspensions,solutions or emulsions in oily or aqueous vehicles, and may containformulatory agents such as suspending, stabilising and/or dispersingagents. Alternatively, the active ingredient may be in powder form forconstitution with a suitable vehicle, e.g. sterile pyrogen-free water,before use.

The compounds of formula (I) may also be formulated in rectalcompositions such as suppositories or retention enemas, e.g. containingconventional suppository bases such as cocoa butter or other glycerides.

In addition to the formulations described previously, the compounds mayalso be formulated as a depot preparation. Such long acting formulationsmay be administered by implantation (for example subcutaneously orintramuscularly) or by intramuscular injection. Thus, for example, thecompounds of formula (I) may be formulated with suitable polymeric orhydrophobic materials (for example as an emulsion in an acceptable oil)or ion exchange resins, or as sparingly soluble derivatives, forexample, as a sparingly soluble salt.

For administration by inhalation the compounds for use according to thepresent invention are conveniently delivered in the form of an aerosolspray presentation from pressurised packs or a nebuliser, with the useof a suitable propellant, e.g. dichlorodifluoromethane,trichlorofluoromethane, dichlorotetrafluoroethane, carbon dioxide orother suitable gas. In the case of a pressurized aerosol the dosage unitmay be determined by providing a valve to deliver a metered amount.Capsules and cartridges of e.g. gelatin for use in an inhaler orinsufflator may be formulated containing a powder mix of a compound offormula (I) and a suitable powder base such as lactose or starch.

The compositions may, if desired, be presented in a pack or dispenserdevice which may contain one or more unit dosage forms containing theactive ingredient. The pack may for example comprise metal or plasticfoil, such as a blister pack. The pack or dispenser device may beaccompanied by instructions for administration.

A proposed dose of the compounds of the invention for administration inman (of approximately 70 kg body weight) is 0.05 to 20 mg, preferably0.1 to 10 mg of the active ingredient per unit dose which could beadministered, for example, 1 to 4 times per day. The dose will depend onthe route of administration and the body weight of the patient. It willbe appreciated that it may be necessary to make routine variations tothe dosage depending on the age and weight of the patient as well as theseverity of the condition to be treated.

For oral administration a unit dose will preferably contain from 0.5 to8 mg of the active ingredient. A unit dose for parenteral administrationwill preferably contain 0.1 to 8 mg of the active ingredient.

Aerosol formulations are preferably arranged so that each metered doseor `puff` delivered from a pressurised aerosol contains 0.2 mg to 4 mgof a compound of the invention, and each dose administered via capsulesand cartridges in an insufflator or an inhaler contains 0.2 to 20 mg ofa compound of the invention. The overall daily dose by inhalation willbe within the range 0.4 to 80 mg. Administration may be several timesdaily, for example from 2 to 8 times, giving for example 1, 2 or 3 doseseach time.

The compounds of formula (I) may be administered in combination withother therapeutic agents, for example to aid absorption of thetherapeutic agent where this is hindered by the patient's condition,such as by gastric stasis associated with migraine. Thus, for example,the compounds may be administered in combination with antimigraineagents such as ergotamine, or antisecretory agents such as ranitidine.They may also be administered in combination with anticancer (e.g.cytostatic) drugs, for example to prevent nausea and vomiting associatedwith these agents. Cytostatic agents with which compounds of formula (I)may be administered include cyclophosphamide; alkylating agents; andplatinum complexes such as cisplatin. Thus, a compound of formula (I)may be presented together with another therapeutic agent as a combinedpreparation for simultaneous, separate or sequential use, for the reliefof nausea and vomiting, or gastrointestinal disorders associated withgastric stasis. Such a combined preparation may be, for example, atwin-pack. A preferred combination comprises a compound of formula (I)with a cytostatic agent, especially cisplatin. In general, the presentlyavailable dosage forms of the known therapeutic agents will be suitablefor use in such combined preparations. Thus, cisplatin may be providedin vials containing 10, 25 or 50 mg of the active ingredient.

The compounds of general formula (I) may be prepared by the processdescribed in British patent application No. 2153821A. Analogousprocesses are also described in European patent application No.86300423.

The efficacy of compounds of formula (I) in the promotion of gastricemptying and their anti-emetic activity have been demonstrated instandard animal models as described below.

(A) Gastric emptying

Test compound:1,2,3,9-tetrahydro-9-methyl-3-[(2-methyl-1H-imidazol-1-yl)methyl]-4H-carbazol-4-onehydrochloride dihydrate. The effect of the test compound on gastricemptying was determined in guinea-pigs by following the progress ofpolystyrene-coated barium sulphate spheres (1 mm diameter) through thegut. The experimental method was based on that described by B. Costallet. al., Eur. J. Pharmacol 91, 197-205, 1983 and B. Cox et. al., Br. J.Pharmacol. 70, 104, 1980.

The spheres (approximately 30 in number) were administered orally in 0.2ml carboxymethylcellulose with 0.05 ml glycerine. At the same time, thetest compound was administered intraperitoneally at doses of 0.001, 0.01and 0.1 mg/kg. The control animals received saline, administeredintraperitoneally, in place of the test compound. Passage of the spheresthrough the gut was monitored at 30-60 minute intervals over a period of2 hours by X-ray location. The number of spheres leaving the stomach wasrecorded and expressed as a percentage of the total.

The results are given in Table 1 below:

                  TABLE 1                                                         ______________________________________                                        Effect on test compound on gastric emptying in the guinea pig                                        Mean % Increase in                                     Dose of test compound  gastric emptying (± s.e.)                           (mg/kg, i.p)*   n      1 hour   2 hours                                       ______________________________________                                        0.001           4      21 ± 8.7                                                                            57 ± 10.5                                  0.01            4      33 ± 3.6                                                                            76.5 ± 11.2                                0.1             4      47 ± 7.6                                                                            68 ± 5.0                                   Saline          5      10 ± 3.7                                                                            30 ± 8.5                                   ______________________________________                                         *Dose expressed as corresponding weight of free base                          n = number of animals                                                         s.e. = standard error                                                    

(B) Anti-Emesis

Test compound:1,2,3,9-tetrahydro-9-methyl-3-[(2-methyl-1H-imidazol-1-yl)methyl]-4H-carbazol-4-onehydrochloride dihydrate.

The effect of the test compound on emesis was demonstrated in ferretsaccording to the general method described by Florezyk, Schurig andBradner (Cancer Treatment Report, 1982 66(1) 187-9) and summarisedbelow. Both the test compound and cisplatin were prepared andadministered in normal saline. The dose of test compound was calculatedas the free base.

a) Control--without test compound

Emesis was induced in groups of 6 male ferrets weighing between 1.5-2kg, by intravenous administration of cisplatin at a dose of 10 mg/kg.The onset of emesis occurred between 38 and 75 minutes after injectionand over a period of 2 hours the number of vomits/retches (episodes) wasin the range 30-62 (average 42±5 vomits/retches per 2 h). Behaviouralchanges characteristic of emesis were also noted.

b) With test compound

The test compound was administered to groups of 6 male ferrets (1.5-2kg) by intravenous administration at doses of 0.01, 0.1 and 1 mg/kg,immediately prior to administration of cisplatin as described above. Theanimals were observed for 3 hours.

The results obtained are given in Table 2 below.

                  TABLE 2                                                         ______________________________________                                                         Intensity                                                            Onset of of emesis                                                                              Duration                                                    emesis   (episodes                                                                              of emesis                                           Compound                                                                              (minutes)                                                                              2 h)     (hours)                                                                              Other observations                           ______________________________________                                        Cisplatin                                                                             38-75    42 ± 5                                                                              2      Behavioural                                  (10 mg/kg                        changes                                      i.v.)                            characteristic of                            (control)                        emesis (e.g. in-                                                              creased or irregular                                                          respiration, back-                                                            ward locomotion,                                                              agitation)                                   Cisplatin                                                                              89-109  17 ± 2.9                                                                            1      Marked reduction in                          (10 mg/kg                        behavioural effects                          i.v.) +                          of cisplatin. In                             Test                             second and third                             Compound                         hours after onset of                         0.01 mg/kg                       emesis, the animals                          i.v.                             rested quietly and                                                            some slept                                   ______________________________________                                        0.1 mg/kg i.v. Emesis and behavioural changes were com-                                      pletely eliminated. After 30-40 minutes the                    1 mg/kg i.v.   animals rested quietly, and some slept.                    

The effect of the test compound on emesis was also demonstratedfollowing intraperitoneal administration, using a similar procedure tothat described above.

Thus cisplatin was administered intraperitoneally to a group of 4 maleferrets at a dose of 9 mg/kg, and the time to onset of emesis and thenumber of emetic episodes were recorded. In a second group of four maleferrets the test compound was administered at a dose of 1 mg/kg i.p. 30minutes before and 1 hour after intraperitoneal administration ofcisplatin. The results are given in Table 3:

                  TABLE 3                                                         ______________________________________                                                       Onset of   Mean no. Mean no.                                                  emesis     of emetic                                                                              of                                         Compound       (minutes)  episodes retches                                    ______________________________________                                        Cisplatin      99.2 (± 8.8)                                                                          6 (± 2)                                                                             43 (± 10)                               (9 mg/kg i.p.)                                                                Cisplatin (9 mg/kg i.p.) +                                                                   emetic response completely                                     test compound  abolished                                                      (1 mg/kg i.p.)                                                                ______________________________________                                    

The following example illustrates the preparation of a compound offormula (I). Temperatures are in °C. Where indicated, solutions weredried over Na₂ SO₄ and solids were dried in vacuo over P₂ O₅ at 50°overnight. Chromatography was carried out using the technique describedby W. C. Still et al (J. Org. Chem., 1978, 43, 2923-2925), on kieselgel9385.

EXAMPLE

1,2,3,9-Tetrahydro-9-methyl-3-[(2-methyl-1H-imidazol-1-yl)methyl]-4H-carbazol-4-onehydrochloride

A solution of2,3,4,9-tetrahydro-N,N,N,9-tetramethyl-4-oxo-1H-carbazole-3-methanaminiumiodide (2.0 g) and 2-methylimidazole (5.0 g) in dry dimethylformamide(30 ml) was stirred, under nitrogen, at 95° for 16.75 h and then allowedto cool. The solid that crystallised was filtered off, washed withice-cold, dry dimethylformamide (3×2 ml) and dry ether (2×10 ml) andthen dried. The resulting solid (0.60 g) was suspended in a mixture ofabsolute ethanol (30 ml) and ethanolic hydrogen chloride (1 ml), andwarmed gently to obtain a solution, which was filtered whilst warm. Thefiltrate was then diluted with dry ether to deposit a solid (0.60 g)which was recrystallised from absolute ethanol to give the titlecompound as a solid (0.27 g) m.p. 186°-187°.

Analysis Found: C,61.9;H,6.4;N,11.8. C₁₈ H₁₉ N₃ O.HCl.H₂ O requiresC,62.3;H,6.1;N,12.1%.

The following examples illustrate pharmaceutical formulations for useaccording to the invention, containing1,2,3,9-tetrahydro-9-methyl-3-[(2-methyl-1H-imidazol-1-yl)methyl]-4H-carbazol-4-onehydrochloride dihydrate as the active ingredient (1.25 g of thehydrochloride dihydrate contains 1.00 g of the free base). Othercompounds of formula (I) may be formulated in a similar manner.

TABLETS FOR ORAL ADMINISTRATION

Tablets may be prepared by the normal methods such as direct compressionor wet granulation.

The tablets may be film coated with suitable film forming materials,such as hydroxypropyl methylcellulose, using standard techniques.Alternatively the tablets may be sugar coated.

Direct Compression

    ______________________________________                                        Tablet                mg/tablet                                               ______________________________________                                        Active Ingredient     4.688   28.125                                          Calcium Hydrogen Phosphate BP*                                                                      83.06   87.75                                           Croscarmellose Sodium NF                                                                            1.8     1.8                                             Magnesium Stearate BP 0.45    0.45                                            Compression weight    90.0    118.0                                           ______________________________________                                         *of a grade suitable for direct compression.                             

The active ingredient was passed through a 60 mesh sieve, blended withthe calcium hydrogen phosphate, croscarmellose sodium and magnesiumstearate. The resultant mix was compressed into tablets using a ManestyF3 tablet machine fitted with 5.5 mm, flat bevelled edge punches.

    ______________________________________                                        Sub-Lingual Tablet                                                                              mg/tablet                                                   ______________________________________                                        Active Ingredient 2.5                                                         Compressible Sugar NF                                                                           62.5                                                        Magnesium Stearate BP                                                                           0.5                                                         Compression Weight                                                                              65.0                                                        ______________________________________                                    

The active ingredient is sieved through a suitable sieve, blended withthe excipients and compressed using suitable punches. Tablets of otherstrengths may be prepared by altering either the ratio of activeingredient to excipients or the compression weight and using punches tosuit.

Wet Granulation

    ______________________________________                                        Conventional Tablet  mg/tablet                                                ______________________________________                                        Active Ingredient    2.5                                                      Lactose BP           151.5                                                    Starch BP            30.0                                                     Pregelatinised Maize Starch BP                                                                     15.0                                                     Magnesium Stearate BP                                                                              1.5                                                      Compression Weight   200.0                                                    ______________________________________                                    

The active ingredient is sieved through a suitable sieve and blendedwith lactose, starch and pregelatinised maize starch. Suitable volumesof purified water are added and the powders are granulated. Afterdrying, the granules are screened and blended with the magnesiumstearate. The granules are then compressed into tablets using 7 mmdiameter punches.

Tablets of other strengths may be prepared by altering the ratio ofactive ingredient to lactose or the compression weight and using punchesto suit.

    ______________________________________                                        Sub-Lingual Tablet  mg/tablet                                                 ______________________________________                                        Active Ingredient   2.5                                                       Mannitol BP         56.5                                                      Hydroxypropylmethylcellulose                                                                      5.0                                                       Magnesium Stearate BP                                                                             1.5                                                       Compression Weight  65.5                                                      ______________________________________                                    

The active ingredient is sieved through a suitable sieve and blendedwith the mannitol and hydroxypropylmethylcellulose. Suitable volumes ofpurified water are added and the powders are granulated. After drying,the granules are screened and blended into tablets using suitablepunches.

Tablets of other strengths may be prepared by altering the ratio ofactive ingredient to mannitol or the compression weight and punches tosuit.

    ______________________________________                                        CAPSULES          mg/tablet                                                   ______________________________________                                        Active Ingredient 2.5                                                         *Starch 1500      97.0                                                        Magnesium Stearate BP                                                                           1.0                                                         Fill Weight       100.0                                                       ______________________________________                                         *a form of directly compressible starch.                                 

The active ingredient is sieved and blended with the excipients. The mixis filled into size No. 2 hard gelatin capsules using suitablemachinery. Other doses may be prepared by altering the fill weight andif necessary changing the capsule size to suit.

SYRUP

This may be either a sucrose or sucrose free presentation.

    ______________________________________                                        A. Sucrose Syrup   mg/5 ml dose                                               ______________________________________                                        Active Ingredient      2.5                                                    Sucrose BP             2750.0                                                 Glycerine BP           500.0                                                  Buffer                                                                        Flavour                                                                       Colour                 as required                                            Preservative                                                                  Purified Water BP to   5.0 ml                                                 ______________________________________                                    

The active ingredient, buffer, flavour, colour and preservative aredissolved in some of the water and the glycerine is added. The remainderof the water is heated to dissolve the sucrose and is then cooled. Thetwo solutions are combined, adjusted to volume and mixed. The syrup isclarified by filtration.

    ______________________________________                                        B. Sucrose-Free         mg/5 ml dose                                          ______________________________________                                        Active Ingredient            2.5                                              Hydroxypropylmethylcellulose USP                                                                          22.5                                              (viscosity type 4000)                                                         Buffer                                                                        Flavour                                                                       Colour                      as required                                       Preservative                                                                  Sweetener                                                                     Purified Water BP to        5.0 ml                                            ______________________________________                                    

The hydroxypropylmethylcellulose is dispersed in hot water, cooled andthen mixed with an aqueous solution containing the active ingredient andthe other components of the formulation. The resultant solution isadjusted to volume and mixed. The syrup is clarified by filtration.

INJECTION

The injection may be administered by the intravenous or subcutaneousroute.

    ______________________________________                                        Injection           μg/ml                                                  ______________________________________                                        Active Ingredient   50  800                                                   Dilute Hydrochloric Acid BP to                                                                    pH 3.5 to pH 3.5                                          Sodium Chloride Injection BP to                                                                   1 ml to 1 ml                                              ______________________________________                                    

The active ingredient was dissolved in a suitable volume of SodiumChloride Injection BP, the pH of the resultant solution was adjusted topH3.5 with dilute hydrochloric acid BP then the solution was made tovolume with sodium chloride injection BP and thoroughly mixed. Thesolution was filled into Type 1 clear glass 5 ml ampoules which weresealed under a headspace of air, by fusion of the glass then sterilisedby autoclaving at 120° for not less than 15 minutes.

METERED DOSE PRESSURISED AEROSOL

    ______________________________________                                        Suspension Aerosol                                                                             mg/metered dose                                                                            Per can                                         ______________________________________                                        Active Ingredient micronised                                                                   0.250        66      mg                                      Oleic Acid BP    0.020        5.28    mg                                      Trichlorofluoromethane BP                                                                      23.64        5.67    g                                       Dichlorodifluoromethane BP                                                                     61.25        14.70   g                                       ______________________________________                                    

The active ingredient is micronised in a fluid energy mill to a fineparticle size range. The Oleic Acid is mixed with theTrichlorofluoromethane at a temperature of 10°-15° C. and the microniseddrug is mixed into the solution with a high shear mixer. The suspensionis metered into aluminium aerosol cans and suitable metering valves,delivering 85 mg of suspension are crimped onto the cans and theDichlorodifluoromethane is pressure filled into the cans through thevalves.

Solution Aerosol

    ______________________________________                                                       mg/metered dose                                                                          Per can                                             ______________________________________                                        Active Ingredient                                                                              0.25         30.0    mg                                      Ethanol BP       7.500        1.80    g                                       Trichlorofluoromethane BP                                                                      18.875       4.35    g                                       Dichlorodifluoromethane BP                                                                     48.525       11.65   g                                       Oleic Acid BP, on a suitable surfactant e.g. Span 85                          (sorbitan trioleate) may also be included).                                   ______________________________________                                    

The active ingredient is dissolved in the ethanol together with theOleic Acid or surfactant if used. The alcoholic solution is metered intosuitable aerosol containers followed by the trichlorofluoromethane.Suitable metering valves are crimped onto the containers anddichlorodifluoromethane is pressure filled into them through the valves.

Inhalation Cartridges

    ______________________________________                                                          mg/cartridge                                                ______________________________________                                        Active Ingredient (micronised)                                                                    0.5                                                       Lactose BP to       25.00                                                     ______________________________________                                    

The active ingredient is micronised in a fluid energy mill to a fineparticle size range prior to blending with normal tabletting gradelactose in a high energy mixer. The powder blend is filled into No. 3hard gelatin capsules on a suitable encapsulating machine. The contentsof the cartridges are administered using a powder inhaler.

I claim:
 1. A method of treatment of gastrointestinal dysfunction whichcomprises administering to a human or animal subject an effective amountof a compound of formula (l) ##STR4## wherein R¹ represents a hydrogenatom or a C₁₋₁₀ alkyl, C₃₋₇ cycloalkyl, C₃₋₇ cycloalkyl-(C₁₋₄)alkyl,C₃₋₆ alkenyl, C₃₋₁₀ alkynyl, phenyl or phenyl-C₁₋₃ alkyl group;and oneof the groups represented by R², R³ and R⁴ is a hydrogen atom or a C₁₋₆alkyl, C₃₋₇ cycloalkyl, C₂₋₆ alkenyl or phenyl-C₁₋₃ alkyl group and eachof the other two groups which may be the same or different, represents ahydrogen atom or a C₁₋₆ alkyl group;or a physiologically acceptable saltor solvate thereof, in combination with ranitidine.
 2. A methodaccording to claim 1 wherein the compound of formula (l) is1,2,3,9-tetrahydro-9-methyl-3-[(2-methyl-1H-imidazol-1-yl)methyl]-4H-carbazol-4-oneor a physiologically acceptable salt or solvate thereof.
 3. A methodaccording to claim 2 in which said1,2,3,9-tetrahydro-9-methyl-3-[2-methyl-1H-imidazol-1-yl)methyl]-4H-carbazol-4-oneis used in the form of a hydrochloride salt.
 4. A method according toclaim 2 in which said1,2,3,9-tetrahydro-9-methyl-3-[2-methyl-1H-imidazol-1-yl)methyl]-4H-carbazol-4-oneis used in the form of the hydrochloride dihydrate.
 5. A methodaccording to claim 1 for the treatment of dyspepsia, refluxoesophagitis, flatulence, peptic ulcer and gastric stasis.
 6. A methodaccording to claim 1 for the treatment of nausea and vomiting.
 7. Apharmaceutical composition comprising a compound of formula (l) ##STR5##wherein R¹ represents a hydrogen atom or a C₁₋₁₀ alkyl, C₃₋₇ cycloalkyl,C₃₋₇ cycloalkyl-(C₁₋₄)alkyl, C₃₋₆ alkenyl, C₃₋₁₀ alkynyl, phenyl orphenyl-C₁₋₃ alkyl group;and one of the groups represented by R², R³ andR⁴ is a hydrogen atom or a C₁₋₆ alkyl, C₃₋₇ cycloalkyl, C₂₋₆ alkenyl orphenyl-C₁₋₃ alkyl group and each of the other two groups, which may bethe same or different, represents a hydrogen atom or a C₁₋₆ alkylgroup;or a physiologically acceptable salt or solvate thereof, incombination with ranitidine.
 8. A pharmaceutical composition accordingto claim 7 wherein the compound of formula (l) is1,2,3,9-tetrahydro-9-methyl-3-[(2-methyl-1H-imidazol-1-yl)methyl]-4H-carbazol-4-oneor a physiologically acceptable salt or solvate thereof.
 9. Apharmaceutical composition according to claim 8 in which said1,2,3,9-tetrahydro-9-methyl-3-[(2-methyl-1H-imidazol-1-yl)methyl]-4H-carbazol-4-oneis used in the form of a hydrochloride salt.
 10. A pharmaceuticalcomposition according to claim 8 in which said1,2,3,9-tetrahydro-9-methyl-3-[(2-methyl-1H-imidazol-1-yl)methyl]-4H-carbazol-4-oneis used in the form of the hydrochloride dihydrate.